The procmail program is used for local mail delivery. In addition to just delivering mail, procmail can be used for automatic filtering, presorting, and other mail handling jobs.
A heap-based buffer overflow flaw was found in procmail's formail utility. A remote attacker could send an email with specially crafted headers that, when processed by formail, could cause procmail to crash or, possibly, execute arbitrary code as the user running formail. (CVE-2014-3618)
All procmail users are advised to upgrade to these updated packages, which contain a backported patch to correct this issue.